[sdantonio]

I'm looking to make a guitar press for forming laminate top archtop guitar plates. The video referenced below uses steel U-channel which I feel is probably way overkill. But I'm looking for ideas for other ways to do it (also at almost 62 I don't feel like lifting a steel unit up onto and off the workbench when I can probably get away with something much lighter.

https://www.youtube.com/watch?v=7VnOp0a7g0I

The upright members can be replaced with 4x4 fir, the column strength of this stuff calculates out to about 4 tons for a 2 ft column.

My question relates more to the bottom and especially the top cross member which will have to handle the pressure on the bottle jack without rupturing. I'm thinking 2 possibilities:

1. 3 pieces of 4x4 fir glued and screwed together something like the attached pic. (total size will be about 4"high x 12"wide x 28"length nominal, the upright members will be attach inside the "U" cutouts in the ends)

2 a torsion table made with (4) 0.75"x3"x28" pieces of MDF with 0.75 inch MDF skins top and bottom

Thanks,
Steven

[bostosh]

Hi,
do you wish to form and glue up archtops?
Need tooling and forming ideas from aerospace?
This would be no problem in aluminum
then you could bake them hard.
I have the surface data and have made dies similar. to

[sdantonio]

Nice work. I actually don't need anything that fancy. Most if the people doing the work in laminate archtop plates (including Benedetto on some of his models) are using a positive and negative MDF mold set (or similar material). And with my meager output of only a couple instruments a year even cheap MDF would last a lifetime. And with the MDF I can easily change the mold to experiment with different parameters such as arching height.

[bostosh]

You could vacuum bag the thin damp wood easily into female form.
I need to vacuum veneer onto flat aluminum next.
D-18 type acoustic aluminum soundboard.

[bostosh]

notice the cyclodial curve on an archtop
What model are you going for.?

[sdantonio]

I've been kicking the idea of vacuum bagging around in my head, but so far the only move I've made towards it was pulling a compressor out of an old fridge and convert it to a pump. I might give it a shot. It certainly will make the glue dry faster.

I have a topological surface map taken directly from a Benedetto. Not saying that that is the perfect curve, but it's a good start.

I like the curtate cycloid curves too. There was a plugin developed for Rhino something like 10 years ago. It was programmed by a young fellow named Mike (I forget his last name) but it was a project that I suggested to him since he was looking for a good programming project. I don't remember if it was a school project or not. But it worked well for Rhino 3. I don't know if it is still available of was ever upgraded for subsequent Rhino releases. With this plugin if you supplied the outline and the long arch it generated the rest.